| 1. |
- Elbornsson, Jonas, 1975-, et al.
(author)
-
Amplitude and Gain Error Influence on Time Error Estimation Algorithm for Time Interleaved A/D Converter System
- 2002
-
In: Proceedings of the 2002 IEEE International Conference on Acoustics, Speech and Signal Processing. - 0780374029 ; , s. 1281-
-
Conference paper (peer-reviewed)abstract
- A method for blind estimation of static time errors in time interleaved A/D converters is investigated. The method assumes tha tamplitude and gain errors are removed before the time error estimation. Even if the amplitude and gain errors are estimated and removed, there will be small errors left. In this paper, we investigate how the amplitude and gain errors influence the time error estimation performance.
|
|
| 2. |
- Grbic, Nedelko, et al.
(author)
-
Soft Constrained Subband Beamforming for Hands-Free Speech Enhancement
- 2002
-
In: Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on. - Orlando, Florida : IEEE. - 0780374029 ; 1, s. 885-888
-
Conference paper (peer-reviewed)abstract
- This paper introduces a new constrained adaptive subband beamformer algorithm for speech enhancement in acoustic telecommunication systems. The solution relies on a pre-calculated source covariance matrix and recursive estimates of background noise- and handsfree signal covariance matrices. The constraint acts as an eye-opening in a vicinity of the near-field location of the source and degradations from steering-vector errors can therefor be made small. The algorithm is applied in subbands using a uniform multi channel over-sampled filterbank. Simulations with real speech recorded in an automobile hands-free environment show 19 dB noise reduction and 20 dB hands-free suppression.
|
|
| 3. |
- Larsson, Erik G., et al.
(author)
-
Space-time block coding for frequency-selective channels
- 2002
-
In: Proc. of IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - 0780374029 ; , s. III-2405-III-2408
-
Conference paper (peer-reviewed)abstract
- We describe the so-called time-reversal space-time block coding (TR-STBC) transmission scheme for communication systems with multiple transmit antennas operating over frequency-selective channels. TR-STBC can be seen as an extension of the orthogonal space-time block codes for flat fading channels. We show that using TR-STBC, a linear filtering at the receiver can achieve an approximate decoupling of the space-time channel into scalar and independent frequency-selective channels and hence any standard maximum-likelihood sequence detector (MLSD) can be used for equalization. Numerical examples are provided to illustrate the performance of the TR-STBC transmission scheme.
|
|
| 4. |
- Nilsson, Mattias, et al.
(author)
-
Gaussian Mixture Model based Mutual Information Estimation between Frequency Bands in Speech
- 2002
-
In: 2002 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, VOLS I-IV, PROCEEDINGS. - 0780374029 ; , s. 525-528
-
Conference paper (peer-reviewed)abstract
- In this paper, we investigate the dependency between the spectral envelopes of speech in disjoint frequency bands, one covering the telephone bandwidth from 0.3 kHz to 3.4 kHz and one covering the frequencies from 3.7 kHz to 8 kHz. The spectral envelopes are jointly modeled with a Gaussian mixture model based on mel-frequency cepstral coefficients and the log-energy-ratio of the disjoint frequency bands. Using this model, we quantify the dependency between bands through their mutual information and the perceived entropy of the high frequency band. Our results indicate that the mutual information is only a small fraction of the perceived entropy of the high band. This suggests that speech bandwidth extension should not rely only on mutual information between narrow- and high-band spectra. Rather, such methods need to make use of perceptual properties to ensure that the extended signal sounds pleasant.
|
|
| 5. |
- Svensson, Lennart, 1976, et al.
(author)
-
Dual-band land mine detection using a Bayesian approach
- 2002
-
In: Proceedings. - Piscataway, NJ : IEEE Communications Society. - 0780374029 ; , s. 1297-1300
-
Conference paper (peer-reviewed)abstract
- The main purpose of the paper is to show that significant improvements in infrared land mine detectors can be achieved, by also considering visual wavelength images. A Bayesian approach, based on dual-band data, is presented that incorporates prior knowledge regarding external parameters such as weather, burial depth and soil moisture. By noting that most relevant backgrounds render rotationally invariant statistics, a low dimensional parameterization of the noise space is derived. Simulations show the performance of three different detectors; first the standard detector used, the matched filter which correlates the infrared image with the known mine shape; secondly a detector which models the spatial statistics of the infrared background while neglecting the visual wavelength data, and thirdly the proposed detector that exploits the full dual-band space. The second detector outperforms the matched filter, and is significantly improved by also utilizing the visual wavelength image.
|
|
| 6. |
- Viberg, Mats, et al.
(author)
-
Analysis of the Combined Effects of Finite Samples and Model Errors on Array Processing Performance
- 1993
-
In: Proceedings of the 1993 IEEE International Conference on Acoustics, Speech, and Signal Processing. - Linköping : Linköping University. - 0780374029
-
Conference paper (peer-reviewed)abstract
- This paper concerns the performance of the class of signal subspace fitting algorithms for signal parameter estimation using narrowband sensor array data. The principal sources of estimation error in such applications are the finite sample effects of additive noise and imprecise models for the antenna array and spatial noise statistics. The covariance matrix of the estimation error when all of these error sources are present is found to be the sum of the individual contributions from each component separately. This simplifying fact allows for the derivation of an overall optimal subspace weighting for a particular array and noise covariance error model. In fact, the resulting algorithm yields the lowest possible asymptotic estimation error variance of any method for the model in question.
|
|
| 7. |
- Viberg, Mats, et al.
(author)
-
Efficient Subspace Fitting Algorithms for Diversely Polarized Arrays
- 1993
-
In: Proceedings of the 1993 IEEE International Conference on Acoustics, Speech, and Signal Processing. - 0780374029 ; , s. 324-327 vol.4
-
Conference paper (peer-reviewed)abstract
- The authors present a statistically efficient algorithm for direction of arrival (DOA) estimation using diversely polarized arrays. The proposed technique requires a multidimensional search over the DOA parameters only, after which the polarization parameters can be calculated explicitly. A comparison with a multiple signal classification (MUSIC) based approach revealed that the method may give significantly improved performance, particularly in scenarios involving highly correlated signals.
|
|
